Composition containing chlorinated hydrocarbons ketones and glycol ethers, for reflowing organic surfaces

ABSTRACT

Compositions for reflowing organic surfaces, such as paints and polystyrene, have been discovered which contain by volume 50 to 90 percent of a liquid chlorinated aliphatic hydrocarbon, 5 to 30 percent of a liquid ketone or alcohol, 2 to 20 percent of glycol ether alkanoate and 0 to 30 percent of an alkyl alkanoate, all of such components having a boiling point below 200* C.

United States Patent Vivian [451 May 16,1972

1541 COMPOSITION CONTAINING CHLORINATED HYDROCARBONS KETONES AND GLYCOLETHERS, FOR REFLOWING ORGANIC SURFACES [72] Inventor: Thomas A. Vivian,Midland, Mich.

[73] Assignee: The Dow Chemical Company, Midland,

Mich.

[22] Filed: Dec. 1, 1969 [21] Appl. No; 881,284

Related U.S. Application Data [63] Continuation-impart of Ser. No.844,662, July 24,

1969, abandoned.

[52] U.S. C1 ..106/285, 106/311, 264/341 [51] Int. Cl. ..C08h 7/22 [58]FieldofSearch ..252/171; 134/38, 40; 106/311,

[56] References Cited UNITED STATES PATENTS 1,557,520 10/1925 Ellis i..252/171 2,969,328 1/1961 Ellenson... ...252/171 2,999,816 9/1961Bennett ..252/171 3,379,549 4/1968 Playfair ..106/31 1 3,020,661 2/1962Miller et al. ..264/341 FOREIGN PATENTS OR APPLICATIONS 773,632 5/1957Great Britain 252/1 71 302,390 12/1928 Great Britain .1 106/190 OTHERPUBLICATIONS Defensive Publication The O.G. Defensive Publication Holt,Defi Pub. of Ser. No. 867,969 filed Oct. 20, 1969 continuation of Ser.No. 684,537 filed Nov. 20, 1967, published in 872 O.G. 1411 on Mar 31,1970 Defensive Pub. No. T 872,012

Primary ExaminerTheodore Morris Altorney-Griswold & Burdick, Herbert D.Knudsen and C. E. Rehberg [57] ABSTRACT 12 Claims, No DrawingsCOMPOSITION CONTAINING CHLORINATED HYDROCARBONS KETONES AND GLYCOLETHERS, FOR REFLOWING ORGANIC SURFACES CROSS-REFERENCE TO RELATEDAPPLICATIONS The present application is a continuation-inpart of myprior application Ser. No. 844,662 filed July 24, 1969 now abandoned.

BACKGROUND OF THE INVENTION Although various solvents have been used toreflow thermoplastic organic surfaces, heat treatment has been theprimary technique used to reflow such surfaces. Of the solvents,chlorinated hydrocarbons are especially effective reflow agents. Thegreatest drawback to the commercial use of chlorinated solvents onpigmented organic materials, however, has been the marked discolorationencountered when these solvents are employed. This discoloration isespecially troublesome when methylene chloride is used to reflowmetallized paints. Also, in reflowing thermoplastic surfaces, crazingand bloom-back are encountered in addition to discoloration.

SUMMARY OF THE INVENTION According to the present invention, reflowcompositions containing by volume 50 to 90 percent of a liquidchlorinated aliphatic hydrocarbon, 5 to 30 percent of a ketone oralcohol, 2 to 20 percent of a glycol ether alkanoate and to 30 percentof an alkyl alkanoate, all of such components having a boiling pointbelow 200 C., have been found to be especially effective reflow agentsfor thermoplastic organic surfaces such as paint.

Organic surfaces are easily reflowed by the compositions of the presentinvention by applying the composition to the surface in the form of aliquid by means of a fine spray, or preferably by vaporizing thecomposition and contacting the surface with a vapor at an elevatedtemperature. During reflow, the organic surface becomes fluid and ismobilized to form an essentially uniform coat over the supporting body.After reflow, the organic surface dries as the solvent is evaporatedunder its own vapor pressure at ambient conditions or by heating thereflowed surface. The dried surface forms an essentially identicalsurface to that of the surrounding area. Thus, by localized reflow,minor imperfections in a small area of an organic surface may be removedwithout creating noticeable distortions in the color or othercharacteristics of the total surface. Alternatively, the whole surfacemay be reflowed to improve gloss in'lieu of buffing.

The chlorinated aliphatic hydrocarbon of the composition of theinvention may suitably be any normally liquid chlorinated hydrocarbonthat is a partial solvent for the organic surface. These chlorinatedhydrocarbons suitably have one to six or more carbon atoms and a boilingpoint of less than 200 C. at atmospheric pressure. Although thehydrocarbon backbone may vary widely, best results have been obtainedwith two to six or more chlorine atoms per molecule. According to thesegeneral limitations, representative compounds of the present inventioninclude: the chlorinated alkanes such as methylene chloride, chloroform,l,land 1,2 dichloroethane, l,l,land l,l,2-trichloroethane, the varioustrichloropropanes, tetrachloropropanes, tetrachlorobutanes,hexachlorobutanes, dichloropentanes and trichlorohexanes; and thechlorinated alkenes such as 1,2- cisand transdichloroethylene,trichloroethylene, tetrachloroethylene, the trichloropropenes,tetrachlorobutenes. In the preferred composition of the presentinvention, the chlorinated aliphatic component is a chlorinated alkaneor alkene of one to three carbon atoms with methylene chloride, 1,2-cisor transdichloroethylene, trichloroethylene and tetrachloroethylenebeing of special interest. Of greatest importance in the presentinvention is methylene chloride.

Although the chlorinated aliphatic hydrocarbon may comprise 50 to 90percent by volume of the composition of the present invention,compositions containing 60 to 80 percent of the chlorinated hydrocarbonare preferred. The chlorinated hydrocarbon may also be stabilizedagainst metal reduction with minor amounts of various stabilizers suchas propylene oxide, butylene oxide, dimethoxymethane or other suitablestabilizers. The use of such stabilizers is preferred when methylenechloride is the chlorinated aliphatic hydrocarbon.

The second component of the reflow composition of the present inventionis a ketone or alcohol which may comprise 5 to 30 percent by weight ofthe reflow composition. Such ketones and alcohols are normally liquid atroom temperature and have a boiling point of about 50 to about 200 C. atatmospheric pressure. Dialkyl ketones and alkanols are preferred in thepresent invention. Representative examples of such ketones and alcoholsinclude: ketones having up to about 1 1 carbon atoms, such as acetone,methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methylisobutyl ketone, ethyl amyl ketone, di-n-butyl ketone, allyl ethylketone, acetyl acetone and methyl hexyl ketone; and alcohols containingup to about eight carbon atoms such as methanol, ethanol, propanol,isopropanol, n-butanol, Z-butanol, pentanol, hexanol, octanol and allylalcohol. Of these ketones and alcohols, acetone, methyl ethyl ketone,methyl isobutyl ketone and butanol are preferred. Although theconcentration of the ketone and alcohol may range from about 5 to about30 volume percent, concentrations of about 10 to about 25 volume percentare preferred.

The third component of the present invention is a glycol etheralkanoate. Such glycol ether esters have one of the terminal hydroxylscapped with an alkyl ether group and the other hydroxy] capped with anacyl group and may be prepared by reacting a glycol according toordinary etherification and esterification reactions. Preferred glycolether esters boil at about to about 200 C. Representative examples ofsuitable glycol ether esters include: ethylene glycol ether esters, suchas ethylene glycol ethyl ether acetate, ethylene glycol butyl etheracetate, ethylene glycol methyl ether acetate, ethylene glycol methylether propionate, ethylene glycol propyl ether acetate, and ethyleneglycol methyl ether butyrate; propylene glycol ether esters, such aspropylene glycol ethyl ether acetate, propylene glycol methyl etheracetate, propylene glycol propyl ether acetate, propylene glycol methylether propionate, propylene glycol methyl ether butyrate and propyleneglycol butyl ether acetate; and butylene glycol ether esters such asbutylene glycol ethyl ether acetate, butylene glycol methyl etheracetate, butylene glycol ethyl ether butyrate and butylene glycol butylether acetate. Preferred lower alkylene glycol ether esters have analkyl ether group of one to four carbon atoms and an acyl group of twoto five carbon atoms. Also preferred in the present invention are theglycol ether esters of ethylene glycol. Especially preferred in thepresent invention is the use of ethylene glycol ethyl ether acetate.Although the glycol ether acetate may be present in amounts of about 2to about 20 percent by volume, compositions containing about 5 to about15 percent by volume of the glycol ether ester are preferred.

The fourth and optional component of the present invention is an alkylalkanoate. Suitable esters of the present invention have a boiling pointof about 50 to about 200 C. and contain about three to about 10 or morecarbon atoms. Representative examples of such esters include methylacetate, ethyl acetate, butyl acetate, hexyl acetate, ethyl propionate,ethyl butanoate, propyl hexanoate and butyl propionate. The use of butylacetate as the ester is preferred especially when organic surfaceshaving a temperature of about 30 C. are reflowed. As the temperature ofthe organic surface is increased, the alkyl ester of the composition ispreferably replaced by the glycol ether ester which is more effectivefor high temperature applications.

The compositions of the present invention are simply prepared by mixingthe individual components in the proportions described above. Therefiowing compositions of the present invention may suitably be appliedto any organic surface that is at least partially soluble in the reflowcomposition to remove minor imperfections from localized areas or fromthe entire surface. The particular reflow composition may vary widely asdifferent organic surfaces and terminal characteristics are desired. Ofthe various organic surfaces that may be reflowed by the compositions ofthe present invention, paints including lacquers and enamels,thermoplastic resins, such as polystyrene, polybutadiene,acrylonitrile-butadienestyrene and similar substances, are preferred,with the reflow of paint being of particular interest.

With the compositions of the present invention, minor imperfections areconveniently and effectively removed from a thermoplastic organicsurface by applying a reflow composition of the invention to the surfaceunder conditions which allow for rapid vaporization of the reflowsolvent. Generally, the reflow compositions of the invention arevolatile enough to be removed under normal room conditions, but some mayrequire heating or other technique to increase the rate of evaporation.

SPECIFIC EMBODIMENTS EXAMPLES l-4 Four pieces of steel measuring 12 X 6inches were completely painted on one side with aluminized acryliclacquer and dried. With a coarse piece of sandpaper, a 3 inch widescratched area was made in the paint along one side. Masking tape wasthen applied to partially cover the scratched and unscratched paintedarea. Various compositions of the invention were then vaporized and hotvapors were contacted with the individual test sections to reflow theexposed paint. The test sections were allowed to dry, the mask wasremoved and the appearance of the reflowed areas was examined incomparison to the part of the metal sheet covered by the masking tapeduring the solvent reflow operation. The discoloration, characteristicsof the reflowed surface and subsequent blistering under high humidityconditions were tested. The blistering experiments were conducted byplacing the reflowed metal plate in a chamber at 100 percent relativehumidity and 95-l40 F. for a period of4 days shortly after the paintedsurface had been reflowed and then observing the surface for blistering.The examples were run under room temperature conditions, about 75 F.,and also under high temperature conditions, about 140 F. In eachexample, the paint was reflowed, minor scratches in the surface wereremoved, a glossy surface resulted and no blistering was encountered.The compositions and results of the discoloration observations are shownin Table l.

Also in the same manner, other compositions containing by volume 50 to90 percent of a liquid aliphatic chlorinated hydrocarbon, 5 to 30percent of a ketone or alcohol, 2 to 20 percent of a glycol ether esterand to 30 percent of an alkyl ester may be employed as a solvent in thevapor reflow of the organic surfaces above. Representative examples ofsuch compositions include compositions containing 5 percent n-butanol,30 percent propyl acetate, 5 percent ethylene glycol methyl etheracetate and 60 percent trichloroethylene; 30 percent dipropyl ketone, 20percent propylene glycol propyl ether acetate and 50 percentperchloroethylene; and 10 percent hexanol, l0 percent butylene glycolethyl ether propionate and 80 percent methylene chloride.

I claim:

l. A composition of matter, consisting essentially of, by volume,

50-90 percent of a liquid chlorinated aliphatic hydrocarbon selectedfrom the group consisting of chlorinated alkanes and alkenes havingone-three carbon atoms and mixtures thereof,

5-30 percent ofa dialkyl ketone of up to l l carbons,

2-20 percent of a lower alkylene glycol ether alkanoate having an alkylether moiety of one-four carbons and an acyl moiety of two-five carbons,

0-30 percent of an alkyl alkanoate, all of such components having aboiling point below 200 C.

2. The composition of claim 1 wherein the chlorinated hydrocarbon ismethylene chloride, 1,2-cisand transdichloroethylene, trichloroethylene,tetrachloroethylene or mixtures thereof.

3. The composition of claim 1 wherein 60 to 80 percent by volume of thecomposition is the chlorinated aliphatic hydrocarbon.

4. The composition of claim 1 wherein the ketone is acetone, methylethyl ketone or methyl isobutyl ketone.

5. The composition of claim 1 wherein 10 to 25 percent by volume is theketone.

6. The composition of claim 1 wherein the lower alkylene glycol etheralkanoate is an ethylene glycol ether alkanoate.

7. The composition of claim 1 wherein 5 to 15 percent by volume is thelower alkylene glycol ether alkanoate.

8. The composition of claim 1 containing ethylene glycol ethyl etheracetate.

9. The composition of claim 1 wherein the chlorinated hydrocarbon ismethylene chloride.

10. The composition of claim 9 wherein the ketone is acetone.

11. The composition of claim 9 wherein the ketone is methyl ethylketone.

TABLE I.REFLOW OF ALUMINIZED ACRYLIC LACQUER Composition, wt. percentDiscoloration Example:

1 70% methylene chloride, 20% methyl ethyl ketone, 10%

ethylene glycol ethyl ether acetate.

2 70% methylene chloride, 20% acetone, 10% ethylene glycol ethyl etheracetate.

3 70% methylene chloride, 20% methyl ethyl ketone, 5%

ethylene lyeol ethyl ether acetate, 5% butyl acetate.

4 70% methy ene chloride, 20% acetone, 5% ethylene glycol ethyl etheracetate, 5% butyl acetate.

Faint dull haze, very little discolora- No haze, no discoloration. v i ylaint haze, very little discolora- No haze, very faint discoloration. Fzi iiit haze, very little discoloration. Very faint haze, very littlediscolora- Faint haze, little discoloration Fziiii thaze, littlediscoloration.

1 Containing 0.5% by weight propylene oxide.

12. The composition of claim 1 wherein the chlorinated 0 hydrocarbon ismethylene chloride,; 1,2-cisor transdichloroethylene, trichloroethylene,tetrachloroethylene, or mixture thereof, the ketone is acetone, methylethyl ketone, methyl isobutyl ketone or mixture thereof and the loweralkylene glycol ether alkanoate is ethylene glycol ethyl ether acetate.

2. The composition of claim 1 wherein the chlorinated hydrocarbon is methylene chloride, 1,2-cis- and trans-dichloroethylene, trichloroethylene, tetrachloroethylene or mixtures thereof.
 3. The composition of claim 1 wherein 60 to 80 percent by volume of the composition is the chlorinated aliphatic hydrocarbon.
 4. The composition of claim 1 wherein the ketone is acetone, methyl ethyl ketone or methyl isobutyl ketone.
 5. The composition of claim 1 wherein 10 to 25 percent by volume is the ketone.
 6. The composition of claim 1 wherein the lower alkylene glycol ether alkanoate is an ethylene glycol ether alkanoate.
 7. The composition of claim 1 wherein 5 to 15 percent by volume is the lower alkylene glycol ether alkanoate.
 8. The composition of claim 1 containing ethylene glycol ethyl ether acetate.
 9. The composition of claim 1 wherein the chlorinated hydrocarbon is methylene chloride.
 10. The composition of claim 9 wherein the ketone is acetone.
 11. The composition of claim 9 wherein the ketone is methyl ethyl ketone.
 12. The composition of claim 1 wherein the chlorinated hydrocarbon is methylene chloride, 1,2-cis- or trans-dichloroethylene, trichloroethylene, tetrachloroethylene, or mixture thereof, the ketone is acetone, methyl ethyl ketone, methyl isobutyl ketone or mixture thereof and the lower alkylene glycol ether alkanoate is ethylene glycol ethyl ether acetate. 